Anti-friction bearing assemblies generally include a bearing and a bearing housing for supporting the bearing therein. Bearing assemblies are used in a wide variety of applications for mainly supporting rotating members. The aforementioned components of anti-friction bearing assemblies are generally formed from different types of material. Specifically the bearing housing is formed from either aluminum or magnesium alloys while the bearing is formed from steel. In anti-friction bearing assemblies it is preferable to approach a zero-gap between the bearing and the bearing housing. This has been achieved by pre-stressing the bearing housing. This method of obtaining a zero gap between the bearing assembly components has several significant disadvantages. The first is that the process is extremely expensive. Secondly, due to the different coefficient of expansions for steel and magnesium, the bearing and bearing housing will expand or contract at differing rates when the assembly is exposed to temperature variations. More specifically, when the assembly experiences a decrease in temperature the housing will contract more rapidly than the bearing. This will result in an unacceptable strickness between the bearing assembly components. Also, when the assemblies are exposed to an increase in temperature the housing will expand at a more accelerated rate than the bearing resulting in a gap between the components which will allow radial play between the same. This will result in undue wear on the bearing assembly. Further, the radial movement between the assembly elements could irreparably damage the rotating member supported by the bearing assembly. Therefore, it has been advantageous to minimize radial play between the compatible components of the bearing assembly.
As discussed above, it is normally advantageous to minimize radial play between the bearing assembly elements. However, it is desirable at times to permit controlled radial play between the bearing and the bearing housing. At high speeds, imperfections in the rotating element result in eccentric movement of the same. The eccentric motions of the rotating element exert an unbalanced force on the bearing housing. This will significantly accelerate the wear on the bearing assembly. Therefore, it has been desirable to dampen the eccentric motions of the rotating element. This can be achieved by permitting controlled radial play between the bearing and the bearing housing.
The following U.S. patents disclose a number of bearing assembly arrangements proposed to overcome the aforementioned concerns: U.S. Pat. Nos. 1,386,255 Hindle; 2,532,327 Parks; 2,534,142 Morton; 2,700,581 Migny; 2,926,051 Cazier; 3,097,026 Sernetz 4,139,317 Hafner; and 4,496,252 Horler.
The above-identified patents disclose a number of bearing assemblies that have been unable to effectively minimize radial play between the assembly components, adequately dampen the eccentric motion of the rotating element and acceptably compensate for changes in temperature.